The following are a selection of frequently asked questions put together by the MD Anderson cancer Center (at the University of Texas). It's great to see research like this coming out on the properties of natural foods, spices etc.

Curcumin is a component of an Indian spice, turmeric. It is estimated that 100 grams of turmeric contains three to five grams curcumin. Curcumin gives a yellow color to turmeric, also present in curry powder. Chemically, curcumin is called diferuloylmethane. Curcumin is yellow-orange in color. Curcumin is used as a natural yellow coloring in mustard, cereals, cheese and butter. In some countries, it is used as a natural coloring agent in the textile industry.

Turmeric has been described in Ayurveda (an ancient Indian system of medicine that means "long life") as an agent that can suppress inflammation. An extensive research during last 50 years has revealed that the anti-inflammatory activity of turmeric is due to curcumin. Curcumin can inhibit both the activity and the synthesis of cyclooxygenase-2 (COX2) and 5-lipooxygenase (5-LOX), as well as other enzymes that have been implicated in inflammation. Curcumin has also been shown to work through numerous other mechanisms. More than 700 genes have been shown to be modulated by curcumin.

Curcumin has been shown to prevent a large of number of cancers in animal studies. Laboratory data indicate that curcumin can inhibit tumor initiation, promotion, invasion, angiogenesis and metastasis.

Epidemiological evidence indicate that incidence of certain cancers is less in people who consume curcumin than in those who do not. Recent evidence indicates that, besides chemopreventive activity, curcumin may also be effective in the treatment of cancer.

Numerous mechanisms have been described for the anticancer activity of curcumin. Inhibition of proliferation of tumor cells, induction of apoptosis (a mode of cell death), inhibition of transformation of cells from normal to tumor, inhibition of invasion and metastasis and suppression of inflammation have been linked with the anticancer activity of curcumin. Down-regulation of COX2, 5-LOX, adhesion molecules, inflammatory cytokines, chemokines, growth factor receptors, vascular endothelial growth factor (VEGF) and transcription factors by curcumin have been linked to its antitumor activity.

Arthritis is also a proinflammatory disease. All current drugs approved for arthritis have anti-inflammatory activity. Anti-TNF (tumor necrosis factor) therapy has been approved for this disease. Curcumin has been shown to both suppress the TNF production and block the action of TNF. curcumin, when applied topically, has been shown to have activity against arthritis.

Crohn's disease is also a pro-inflammatory disease. All current drugs approved for this disease have anti-inflammatory activity. Anti-TNF therapy has been approved for this disease. Curcumin has been shown to both suppress the TNF production and the TNF action. Curcumin taken orally has been shown to have activity against Crohn's disease.

There have been at least 10 different clinical trials performed with curcumin in patients with different diseases. These are mostly pilot studies that are proof of concept type. More than 10 trials are now in progress in the United States and other countries.

According to one of the phase I studies, curcumin was found to be safe in human subjects even when consumed at up to eight grams per day for three months. In spite of this finding, it is recommended that one take a lower dose of 500 mg/day, increasing to a higher dose gradually, if needed. Look for signs of both potential toxicity and improvement by talking to your body and to your doctor.

Was other dietary intake of curcumin monitored closely during each trial?

Most trials have not monitored dietary curcumin because only people of the Indian subcontinent routinely use curcumin in their diets. A few trials (Plummer, 2001, and Sharma, 2001) have asked patients not to eat foods containing curcumin.

What is the basis for the large doses?

It is typical in medicine to find out the maximum tolerated dose (MTD).

Is it plausible to explore the lowest dose that provides the maximal benefit?

Yes, in fact there is some evidence that curcumin is an antioxidant even at low doses. There is also evidence that curcumin taken on an empty stomach is more effective.

Do subjects experience dyspepsia, ulcers, dermatitis and other side effects when taking curcumin in the pure form or as a component of curry or turmeric?

A few people have experienced diarrhea or transient nausea, but no major toxicity has been detected.